Sigmoidal Decoding from Distinct M1 Spiking Populations and LFP Band Power for Locomotion Speed in Mice.

Authors

Ghazaal Tahmasebi, Sophia Vargas, Christian Fofie Kuete, Pegah Haghighi, Elysandra Solis, Ajaree Massaquoi, Joseph Pancrazio

Published in

Journal of neurophysiology. Jul 22, 2026. Epub Jul 22, 2026.

Abstract

The extent which the primary motor cortex (M1) encodes locomotion speed is relatively unexplored, with some studies suggesting linear or gain-modulated tuning. Here we show that there are neurons in the mouse M1 where spiking relates to locomotion speed in a manner consistent with a sigmoidal state-transition model implemented by two functionally distinct neural populations. In addition, sigmoidal framework extends to local field potential (LFP) band power, enabling a direct within-animal comparison of spiking and LFP-based speed encoding. We recorded extracellular activity (5,889 single units, 384 channels) using chronic 32-channel laminar arrays in 8 mice locomoting on a motorized treadmill over 8 weeks, with actual speed tracked via DeepLabCut. Unsupervised clustering of temporal firing rate profiles identified two groups: speed-positively related (70.8%), and speed-inversely related (29.2%) units. Sigmoidal models of speed-positively related rate tuning significantly outperformed linear and quadratic alternatives for both populations, and the two clusters shared a common speed threshold (~2.3 m/min) consistent with a shared subcortical locomotor gate. When exploring decoding, the minority speed-inversely related population demonstrated significantly higher decoding accuracy via inverse-sigmoid transformation compared to the larger speed-positively related population or all units combined, an advantage that generalized across animals via leave-one-animal-out cross-validation. LFP band power also exhibited sigmoidal tuning relative to locomotion speed, but decoded speed with lower fidelity. These findings suggest a push-pull sigmoidal architecture for spiking-based speed representation in M1 and demonstrate that LFP provides a complementary and stable signal for coarser speed estimation.

PMID:
42484995
Bibliographic data and abstract were imported from PubMed on 22 Jul 2026.

Read full publication at:
Please sign in to see all details.

Stats

1-terrible, 9-excellent. How would you rate this publication? Sign in in to submit your rating.

Post a comment

You need to be signed in to post comments. You can sign in here.

Comments

There are no comments yet.